BenchReady — M1 MacBook Air startup route worksheet
MacBook Air · M1 (2020)

Stop for liquid exposure, swelling, damaged power accessories or unusual heat. This route does not ask you to erase storage, reinstall macOS or open the laptop.

Date: _____   MacBook Air M1 (2020) confirmed: yes / no / unknown
macOS version if known: _____   Safety stop or concern: _____

LAST VISIBLE STAGE — choose only what was observed
[ ] No visible screen   [ ] Apple logo/progress   [ ] Startup options
[ ] Login window   [ ] Desktop   [ ] Unknown / not attempted
What happened next, and when: _____

BUILT-IN / EXTERNAL COMPARISON
Built-in screen: _____   Connected display: _____
Cable / adapter / display input: _____   Any change between checks: _____
External comparison not performed because: _____

STARTUP SOFTWARE COMPARISON — only if attempted safely
Normal startup symptom: _____   Safe startup symptom: _____
Safe mode verified / not verified / not reached / not attempted

HARDWARE DIAGNOSTICS — separate from safe mode
macOS 26+ selected test / earlier automatic test / version unknown
Test selected if applicable: _____   Result or reference code: _____
Not performed / interrupted / result unknown. Reason: _____

Chosen next record: _____   Backup readiness: _____
Still unknown / question for service: _____

READ BEFORE USING
Choose by what you can observe
Confirm MacBook Air with the M1 chip, released in 2020. If the model or chip is uncertain, use Identify your device before following a task.
No response to power is apparent — Start with the USB-C charging record. Do not infer that a black display proves a power failure.
The built-in screen stays blank or stops during startup — Record the last visible stage in the blank-screen task. Note whether startup options were visible, unavailable or not attempted.
The built-in screen works; the connected display does not — Use the external-display record. Keep the cable, adapter and display input beside the result.
You can reach startup options and want to compare startup software behavior — Use the safe-mode comparison. Record whether the same symptom occurs in normal and safe startup.
You want to record a hardware diagnostic result — Use Apple Diagnostics. Keep the installed macOS branch and the actual result together.
Keep the two startup tools distinct
For Apple silicon, safe mode uses the startup volume and Shift with Continue in Safe Mode. Apple Diagnostics uses Command-D from startup options. Open the matching task for the full sequence.
Diagnostics in macOS Tahoe 26 and later asks you to select a test; earlier versions run automatically. An unavailable screen is an unperformed check, not a passed diagnostic.
A changed symptom in safe mode or on another display is a comparison result. It does not by itself establish which component needs replacement.

NEXT STEPS
Record USB-C charging: https://csl-15-device-repair.pages.dev/tasks/mba-m1-usbc-charge/
Record the last visible screen: https://csl-15-device-repair.pages.dev/tasks/mba-m1-blank-screen/
Compare the external display: https://csl-15-device-repair.pages.dev/tasks/mba-m1-external-display/
Compare safe and normal startup: https://csl-15-device-repair.pages.dev/tasks/mba-m1-safe-mode/
Record Apple Diagnostics: https://csl-15-device-repair.pages.dev/tasks/mba-m1-diagnostics/
Build a startup service handoff: https://csl-15-device-repair.pages.dev/pack/mba-m1-startup-handoff/

OFFICIAL GUIDANCE
Apple: If your Mac starts up to a blank screen: https://support.apple.com/en-us/102575
Apple: Start up your Mac in safe mode: https://support.apple.com/guide/mac-help/start-up-your-mac-in-safe-mode-mh21245/mac
Apple: Use Apple Diagnostics to test your Mac: https://support.apple.com/en-us/102550

Original blank worksheet · checked 17 October 2026. Keep filled records private. Do not add passwords, PINs, recovery keys or serial numbers. This TXT is not an importable record; use the linked task to save observations and export a restorable JSON.